Difference between revisions of "IF Directive"

Revision as of 14:04, 4 June 2009

Class

Applications

Purpose

Compiler directives to allow inclusion or exclusion of source code based on a condition

Syntax

#IF <expN1> | <expL1>

<statements1>

[#ELIF <expN2> | <expL2>

<statements2>...

#ELIF <expNN> | <expLN>

<statementsN>]

[#ELSE

<statements_else>]

#ENDIF

See Also

COMPILE, #DEFINE, DO, DO CASE, IF, #IFDEF, #INCLUDE, SET COMPILE, SET DEVELOPMENT, #UNDEF

Description

The #IF compiler directive can be used to allow inclusion or exclusion of source code based on a condition. The condition can be a numeric expression, <expN1>, or any valid expression evaluating to a logical true (.T.) or false (.F.), <expL1>, and is evaluated at compile time. If the <expL1> evaluates to true or the <expN1> evaluates to a nonzero value, the <statements1> that follow are included in the compiled program file and the compilation continues after the #ENDIF. The <statements1> can be any valid Recital 4GL commands. If the <expL1> evaluates to false or the <expN1> evaluates to zero, the <statements1> are excluded and any included #ELIF directives are evaluated in turn in a similar way. If a #ELIF condition evaluates to a non-zero value or to true, the statements that immediately follow are included in the compiled program file and the compilation continues after the #ENDIF. If no #ELIF directives are specified, or if they all evaluate to zero or to false, a check is made for a #ELSE directive and its <statements_else> included in the compiled file if it exists.

This directive can only be used in compiled programs.

Example

#IF OS() = "Windows Servers"
    dirterm = "\"
#ELIF OS() = "Linux Servers"
    dirterm = "/"
    set filecase on
#ELIF OS() = "OpenVMS Servers"
    dirterm = "]"
#ELSE
    dirterm = "/"
    set filecase on
#ENDIF

Products

Recital Database Server, Recital Mirage Server, Recital Terminal Developer